Curated OER
Expansion By Minors
For this algebra worksheet, students solve matrix problems identifying the Minors and solving for x. There are 14 problems to be solved.
Wolfram Research
Wolfram Math World: Quadratic Equation
This MathWorld site shows how to derive the quadratic formula.
Help Algebra
Help algebra.com: Quadratic Formula
This presentation of the quadratic equation includes a discussion on the discriminant and a derivation of the quadratic formula.